This invention relates to a tool adaptor, particularly to one which features two differently sized coupling ends that can be changeably coupled to differently sized coupling sleeve heads of tool bits.
There have existed various forms of tool adapters for coupling to tools. As shown in FIG. 1, an impact screw driver typically includes an impact receiving member 1 that imparts a rotary motion to a transmitting unit or adapter 2 through a cam mechanism (not shown) and the transmitting unit 2 usually has a coupling end 2a of square or hexagonal cross-section integrally formed therewith. The coupling end 2a is adapted for being fitted in the coupling sleeve head 3 of the tool bit 4, such as, a wedge-shaped screw driver blade or philliphs-head, cross slotted screw driver, by means of the engagement of a spring biassed ball.
Generally, the coupling sleeve head 3 is manufactured in two specifications, 3/8 inches and 1/2 inches, and to match the sizes of the coupling sleeve head, the impact screw driver usually has a 3/8 or 1/2 inch coupling end. In some cases, inconveniences are caused to the manufacturers in processing different sized tools to supply their clients whose requirements are not uniform.